×
INTELLIGENT WORK FORUMS
FOR ENGINEERING PROFESSIONALS

Log In

Come Join Us!

Are you an
Engineering professional?
Join Eng-Tips Forums!
  • Talk With Other Members
  • Be Notified Of Responses
    To Your Posts
  • Keyword Search
  • One-Click Access To Your
    Favorite Forums
  • Automated Signatures
    On Your Posts
  • Best Of All, It's Free!
  • Students Click Here

*Eng-Tips's functionality depends on members receiving e-mail. By joining you are opting in to receive e-mail.

Posting Guidelines

Promoting, selling, recruiting, coursework and thesis posting is forbidden.

Students Click Here

Jobs

Bleeding hydraulic cylinders

Bleeding hydraulic cylinders

Bleeding hydraulic cylinders

(OP)
While this may seem very fundamental, how does one bleed a hydraulic cylinder when the rod end port has a welded tube that leads down to its flare connection at the head end. This cylinder lies horizontal when retracted and is tilted rod end up when extended. It always seems to trap some air. I am bleeding by simply loosening the fitting at the end that I am stroking it to to let the air/oil out.

RE: Bleeding hydraulic cylinders

First of all, is the air going to cause a problem if it trapped in the annulus of the cylinder when the cylinder supports the load on the full bore?

Does the cylinder ever go over centre? If it does not then leave the air in and let the oil absorb it.

If you really do need to remove the air, split the fitting at the end of the welded tube and start the cylinder extending. Tighten the fitting before the cylinder stops otherwise when the cylinder relaxes, it will pull air into the tube.

This is not a fundamental problem, removing air from cylinders can be very tricky, the best idea is to stop it getting in in the first place.


Good luck!

H'mech

RE: Bleeding hydraulic cylinders

when first installing or re installing - pressurise piston
end to full stroke - several times ... avoid accidents

& injuries.

RE: Bleeding hydraulic cylinders

Hmech has good synopsis. Maybe it matters, maybe not.

If load reverses, can be very dangerous expecially at startup. Our shop threw a big conveyor on the ground as the load reversed (past center) and they found out that meter out flow controls and counterbalances only work with liquids, not compressible air!

Loosening the fitting works if JIC flare, but caution if split flange or Oring face seal. The oring can be slightly extruded and leak or blow out later.

kcj

Red Flag This Post

Please let us know here why this post is inappropriate. Reasons such as off-topic, duplicates, flames, illegal, vulgar, or students posting their homework.

Red Flag Submitted

Thank you for helping keep Eng-Tips Forums free from inappropriate posts.
The Eng-Tips staff will check this out and take appropriate action.

Reply To This Thread

Posting in the Eng-Tips forums is a member-only feature.

Click Here to join Eng-Tips and talk with other members!


Resources

Research Report - Mass Customization Placing Design in the Customers Hands
Products come in all shapes and sizes, and customers demand solutions tailored to their needs. With mass customization software, these two facts can be reconciled in an automated, customer-facing experience called a product configurator. In this engineering.com research report, we examine the different levels of mass customization with the pyramid of product configurators. Taking a look at real-world case studies, we discover how the highest level of the pyramid can enable true engineering automation, saving time and increasing customer satisfaction. Download Now
Research Report - Test and Simulation Survey
We at engineering.com continually hear how engineers and designers will be doing simulation, such as FEA and CFD, and that they will be doing it early in the design cycle. Is this wishful thinking? We found out what it is really like in industry. Read more now. Download Now
White Paper - Effects of AIA Quick Guide to UL 489 or UL 1077
The function of a circuit breaker is to provide overload (thermal) and short-circuit (magnetic) protection to a circuit and its downstream components. A circuit breaker functions like an airbag in a car, protecting circuit components and people by tripping the circuit to interrupt the current flow if it detects a fault condition in the control system. Download Now
White Paper - Guide to Integrate Large-Format Additive
As with any new technology, getting into large-format 3D printing begins with investigation. The first question may be a simple one: what does “large-format” mean? For 3D printers, “large” is a relative term. Many extrusion-based (FFF) 3D printers are referred to as desktop machines, because they fit on table space. Some of these have very respectable build volumes – but when it comes to “large-format,” the machines will need their own dedicated floor space. Large-format 3D printers have significant build volumes and are most often found in professional settings, like manufacturing facilities and R&D centers. Download Now

Close Box

Join Eng-Tips® Today!

Join your peers on the Internet's largest technical engineering professional community.
It's easy to join and it's free.

Here's Why Members Love Eng-Tips Forums:

Register now while it's still free!

Already a member? Close this window and log in.

Join Us             Close